1. Field of the Invention
The present invention relates generally to tools and equipment used in the trucking industry, and more specifically to a combination device for pulling the lock pin handle for a longitudinally adjustable tandem axle unit on a semitrailer. The present invention also serves to indicate the desired position for the tandem unit as the trailer is moved, and other functions.
2. Description of the Related Art
Many semitrailers are equipped with longitudinally adjustable tandem axle assemblies, where the position of the tandem unit may be adjusted over some range in order to better distribute the load over the wheels, support the rear of the trailer during loading, or for other reasons. These tandem axle units are normally secured to the trailer subframe by a series of large, heavy spring loaded pins which project laterally through mating passages in the subframe and tandem axle unit, with a handle being provided to release the pins for tandem adjustment.
However, the shear force on the pins, particularly when the pins are somewhat worn and grooved, along with the spring tension urging the pins into their locked position, result in it being necessary to apply a fair amount of force to the handle while rocking the trailer in order to release the pins. In the past, a driver has required the assistance of a second party to pull on the tandem release handle, while the driver maneuvers the truck back and forth. This is potentially dangerous to the assistant unless all parties involved know precisely what they are doing and communicate well, as the person pulling the release handle is very close to the left side dual tandem wheels of the assembly. Even though the wheels should not move appreciably, there is always the possibility of contact with the wheels by the assistant.
Accordingly, tools have been developed in the past to apply a releasing force to the release handle while the driver repositions the truck from the cab. Even with the use of such a tool, the driver may be required to make several trips in and out of the cab to check on the progress of the operation, as he must (1) attach the tool to apply a tensile force to the handle, (2) return to the cab to rock the trailer, (3) perhaps leave the cab to see if the rocking action has released the pins, (4) return to the cab to move the tractor and trailer relative to the tandem axle assembly, (5) leave the cab to check on the relative position of the tandem assembly, release the unlocking force on the lock pin handle as required, and remove the tool, (6) return to the cab to move the tractor and trailer slightly to cause the pins to lock the tandem assembly in its new desired position, (7) leave the cab to confirm that the tandem is locked in position as desired, and (8) finally return to the cab for the drive. Moreover, it may be necessary for the driver to repeat steps (2) and (3) one or more times, if the initial rocking of the truck has failed to release the tandem locking pins. This operation is very frustrating for truckers, as they are normally paid by the mile, and the loss of five, ten, or fifteen minutes or more while attempting to adjust the position of the tandem unit on their trailer, eats up a substantial fraction of time which they could be spending on the road.
Even if the driver is aware of the release of the locking pins for the tandem axle unit and proceeds to reposition the tractor and trailer relative to the tandem, the driver still must leave the cab to check the position of the tandem. If the driver has not moved the tractor and trailer sufficiently far, or has moved the rig too far, then he must return to the cab and move the tractor and trailer again in an attempt to position the tandem unit at least close to the desired position so he can release the unlocking position of the lock pin release handle and begin the trip.
It will be seen that the positional adjustment of a tandem axle unit on a semitrailer is a major hassle for a truck driver, even where a tool is applied to the lock pin release handle for pulling the release handle automatically. Accordingly, a need will be seen for a puller and locator tool for use with tandem axle units of semi trailers, which tool serves to automatically apply a release force to the tandem lock pin release handle and also indicates the proper repositioning of the tandem unit to the desired position. With the use of the present tool, the driver need only attach the tool to the tandem unit and lock pin release handle and secure the locator to the trailer as desired, return to the cab to maneuver the tractor and trailer to release the lock pins, move the tractor and trailer the predetermined distance to reposition the tandem unit as desired (the desired position is indicated by the locator of the present tool), and leave the cab a second time to remove the tool and locator respectively from the tandem axle unit and trailer. The present release handle puller and tandem locator tool thus saves a considerable amount of time for a driver, and also provides other functions as well (i.e., an accessory permits it to be used to pull the release for the fifth wheel coupling of the tractor).
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 3,618,969 issued on Nov. 9, 1971 to John J. Glassmeyer, titled xe2x80x9cApparatus For Positioning Trailer Suspension Frame,xe2x80x9d describes an automated mechanism for releasing the lock pin handle from its pulled position when the tandem axle unit has been repositioned to the desired location. The Glassmeyer mechanism goes beyond the scope of the present invention, in that it automatically releases the unlocking force on the lock pin handle to allow the lock pins to engage the desired corresponding holes in the trailer subframe. However, the Glassmeyer mechanism is a permanent installation and is integrated with the trailer; it cannot be removably applied to a trailer as a portable tool which is retained by the driver, as is the case with the present puller and locator tool. While a driver who drives for a company whose trailers are equipped with the Glassmeyer mechanism would enjoy its benefits, the mechanism does nothing for drivers who have occasion to pull trailers not equipped with the Glassmeyer apparatus.
U.S. Pat. No. 5,065,488 issued on Nov. 19, 1991 to Richard L. Chapman et al., titled xe2x80x9cTandem Axle Trailer Pin Extracter Device,xe2x80x9d describes a portable device generally comprising a tube with an internal spring and handlebars projecting therefrom. The spring provides a tensile force for hooks which project from opposed slots in the sides of the tube, with the handlebars being connected to the opposite end of the spring and projecting from the slots. The hooks are secured to the tandem lock pin release handle of the trailer, and the handlebars pulled and secured in retainer grooves at the opposite end of the slot, with the spring thus providing a tensile force on the lock pin release handle. The Chapman et al. device has no means of securing positively to the tandem axle slider frame, and thus requires a separate brace arm which bears against the ground while the tool is installed. In contrast, the present tool attaches securely to the tandem slider frame adjacent to the lock pin release handle, and does not require any additional attachment means or bracing. Also, the present tool is adjustable in length, to allow for different distances between the tandem slider frame and the outer edge of the trailer where the present tool may be manipulated and observed from the cab. Moreover, Chapman et al. describe the removal of their tool from the trailer once the lock pin release handle has been pulled, leaving the driver to guess at the amount of movement required to reposition the trailer body relative to the tandem axle unit. The locator provided with the present tool provides a positive indication to the driver that the trailer has been moved the desired amount, with the driver being able to observe this indication from the cab.
U.S. Pat. No. 5,199,732 issued on Apr. 6, 1993 to Herbert D. Lands et al., titled xe2x80x9cApparatus For Unlocking A Bogie On A Tractor-Trailer Rig,xe2x80x9d describes a permanently installed, pneumatically powered system for providing the required force for releasing the tandem locking pins. FIG. 2 of the Lands et al. disclosure illustrates an exemplary mechanism for retracting and extending the tandem unit locking pins, as is known in the art and which mechanism is operated by the tool of the present invention. While Lands et al. provide various other features, such as automatic pin extension in the event of the emergency brakes of the tandem unit being disengaged during operation, the mechanism is not portable in the sense that it cannot be quickly removed from the tandem unit by hand, without the use of tools, and carried by the driver in the cab of the truck. Also, Lands et al. do not address the problem of precisely locating the tandem unit as desired in its new position relative to the trailer, as provided by the locator of the present tandem axle unit repositioning tool.
U.S. Pat. No. 5,326,144 issued on Jul. 5, 1994 to Clarence D. Forcier, titled xe2x80x9cSemitrailer Sliding Tandem Pin Puller,xe2x80x9d describes a device similar to that of the ""488 U.S. Patent to Chapman et al., discussed further above. The Forcier device comprises a tube with a coil spring installed concentrically therein, with a loop at the end of the spring for connecting to the locking pin release handle and a clamp at the end of the tube for securing the device to the edge of the trailer. Forcier also provides an optional flag or marker which extends past the end of the tube as the spring retracts when the lock pin handle is pulled for release. However, it is noted that the Forcier device secures to the trailer, rather than securing to the frame of the tandem wheel assembly. This will result in the device becoming overextended and possibly pull it loose from the trailer if the driver continues to move the trailer after the lock pins are pulled, as the spring attachment will remain with the lock pin handle while the opposite trailer attachment end moves with the trailer. Thus, a driver using the Forcier device would be required to leave the cab and remove the device once the pins are pulled to free the tandem axle unit. The driver would still be left to guess as to the position of the tandem unit for repositioning the unit, with multiple attempts perhaps being required to position the tandem unit as desired. The locator of the present tool does not provide an indication when the release handle is released, as does the Forcier tool, but does provide an indication when the tandem unit has been properly repositioned, which Forcier does not.
U.S. Pat. No. 5,449,190 issued on Sep. 12, 1995 to William G. Ford, titled xe2x80x9cTrailer Pin Puller,xe2x80x9d describes a device which secures to the lock pin release handle and trailer side in much the same manner as the Forcier device discussed immediately above. However, the Ford device includes a threaded advance shaft connected to the outboard end of the spring (i.e., opposite its attachment end to the pin release handle), with which the tension on the spring may be adjusted. The same problems as addressed in the discussion of the Forcier device are seen to exist with the Ford device, i.e., part of the tool is connected to the tandem unit, while the other part is connected to the trailer. The device must be disconnected from the handle and trailer after the lock pins have been released and before the trailer is repositioned on the tandem unit, in order to avoid pulling the device loose.
U.S. Pat. No. 5,564,725 issued on Oct. 15, 1996 to Russell S. Brazeal, titled xe2x80x9cPneumatically Operated Slider Locking Mechanism,xe2x80x9d describes a pneumatically powered assisting device for operating the otherwise conventional mechanism for retracting and extending the locking pins for a tandem axle unit. Pulling the release handle actuates the pneumatic system, which provides pneumatic pressure to retract the pins. The Brazeal pneumatic system thus teaches away from the present tool, as Brazeal does not require any form of external tensile spring pressure to pull the handle, due to the pneumatic assist. Also, the Brazeal system is. permanently installed on the trailer and relies upon the integral pneumatic system of the trailer, unlike the present portable tool.
U.S. Pat. No. 5,678,834 issued on Oct. 21, 1997 to Glenn Wise, titled xe2x80x9cTandem Positioning Assist Tool,xe2x80x9d describes a device for applying tensile force to the lock pin release handle on a tandem axle unit of a semitrailer. The device comprises a relatively bulky, generally rectangular frame which is unfolded and removably secured to the tandem subframe. Different bases for the frame allow it to be used with different types of trailers which have different lock pin release handle systems. Wise also provides for an indicator to show the driver in the cab when the handle has moved, to indicate the release of the lock pins. However, the Wise device does not provide any indication of the proper repositioning of the tandem axle unit once the pins have been released. The driver must guess at the proper position, which may require two or three trips from the cab to the trailer, using the Wise device. In contrast, the present tool provides an accurate indication when the tandem unit has been repositioned to the desired location, which feature is not found in any other tandem axle adjustment tools known to the present inventor.
U.S. Pat. No. 5,833,253 issued on Nov. 10, 1998 to Timothy V. Hess, titled xe2x80x9cLocking Mechanism For Movable Subframe Of Tractor-Trailers,xe2x80x9d describes a system more closely related to the pneumatically powered system disclosed in the Brazeal ""725 U.S. Patent, than to the present invention. As in the Brazeal system, the Hess system is a permanently installed device integral with the trailer, rather than being a portable, manually operated tool as in the present puller and locator tool.
U.S. Pat. No. D-289,360 issued on Apr. 21, 1987 to Orville H. Westcott, titled xe2x80x9cTruck Tool,xe2x80x9d illustrates a design comprising a flat bar with a hook at each end, and a narrow plate extending from one end and perpendicular to the plane of the bar. The Westcott Design Patent provides no indication of function for the device, and no spring means for applying tensile force to the lock pin release handle of a tandem axle unit, nor indicator means for indicating when the tandem unit is properly positioned, are apparent in the Westcott disclosure.
British Patent Publication No. 584,416 accepted on Jan. 14, 1947 to Ensor Caravans Ltd., titled xe2x80x9cImprovements In Trailers And Like Road Vehicles,xe2x80x9d describes a light trailer frame having a single longitudinally adjustable axle. The position of the axle is adjusted by a crank mechanism at one end of the trailer. The ""416 British Patent Publication teaches away from the present tool, as no release handle is required with the mechanism of the British Patent Publication. The threaded shaft of the crank mechanism provides sufficient frictional force to preclude movement of the assembly, without need for locking pins as found in larger semitrailer tandem axle units.
Finally, Canadian Patent Publication No. 566,681 issued on Nov. 25, 1958 to Charles B. Sheppard et al., titled xe2x80x9cPre-Selector For Positioning Running Gear Relative To Trailer Body Load,xe2x80x9d describes a tandem axle adjustment mechanism which is permanently installed and integrated with the trailer assembly, unlike the present portable tool. Rather than providing an indicator or locator to show when the tandem unit has been repositioned at the desired location beneath the trailer, Sheppard et al. provide a mechanism which automatically resets the lock pins according to prior adjustment when the tandem unit is repositioned to the predetermined location. Otherwise, the Sheppard et al. mechanism is more closely related to the permanently installed, integral mechanisms of the U.S. Patents to Lands et al., Brazeal, and Hess, than to the present portable puller and locator tool for semi trailer tandem axle units.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention comprises a portable tool for pulling the lock pin release handle for adjusting the position of a tandem axle unit on a semitrailer. The present tool is actually a combination device, and may be used as a locating device for remotely indicating the predetermined proper position of the tandem unit during adjustment, thus precluding need for the driver to repeatedly leave the cab to check the position of the tandem unit during adjustment. The present tool may further include means for pulling the release mechanism on the fifth wheel of the tractor, and its elongate configuration allows it to be used as a xe2x80x9ctire thumper,xe2x80x9d for providing a rough idea of tire inflation.
The present tool comprises an elongate telescoping tube having a smaller diameter tube or rod whose distal end temporarily secures to the tandem axle unit of the semitrailer for use in pulling the lock pin release handle thereof. The larger diameter tube includes a slot with a series of detents therein, into which a mating pin extending from the smaller diameter rod or tube may be selectively placed to adjust the overall length of the device. A spring extends from near the handle end of the larger diameter tube, and is removably secured to the lock pin release handle of the trailer. By adjusting the telescoped length of the tool, tension is applied to the spring and thus to the lock pin release handle, urging it from its locked position when any shear force being applied to the lock pins is released by slight movement of the truck and trailer.
The present tool may also be used to determine the proper repositioning of the tandem axle unit. A marker is suspended from the side of the trailer opposite the desired relocation point of the axle unit, where that point will be substantially aligned with the lock pin release handle. When the trailer is moved (either forwardly or rearwardly) to the point where the indicator contacts the puller tool handle, this condition is observable from the cab, indicating that the tandem unit has been relocated to substantially the proper position. Alternatively, the locator may be suspended on a line having a length extending below the tool, substantially equal to the distance which the tandem unit must be moved. When the locator line drags across the tool until the locator reaches the handle, the driver knows the proper position has been reached.
The larger diameter or handle portion of the present tool may further include a hook extending therefrom, for reaching the release rod for the fifth wheel of the tractor. Thus, the present tool may be used as a release for the semitrailer connected to the tractor, in addition to the other functions described above, thereby eliminating the need for a trucker to carry multiple tools for accomplishing the multiple tasks which may be handled by the present combination tool.
Accordingly, it is a principal object of the invention to provide an improved tool for use in remotely pulling the lock pin release handle for an adjustably positionable tandem axle unit in a semitrailer.
It is another object of the invention to provide an improved tool for such use, including locator means for determining the proper repositioning of the tandem axle unit to the desired predetermined position.
It is a further object of the invention to provide an improved lock pin release handle puller and tandem unit locator tool, including means for releasing the release rod for the fifth wheel of a truck tractor unit.
An additional object of the invention is to provide an improved tool including means for adjusting the length thereof for different spans between the lock pin release handle and trailer side in different trailers.
Still another object of the invention is to provide an improved tool which is portable and easily carried by a truck driver.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.